Systemic sclerosis and pseudomesotheliomatous adenocarcinoma of the lung.
Posted Dec 21 2009 12:00am
By Yoshimi R. and Colleague
A 55-year-old man, diagnosed with systemic sclerosis (SSc) for 20 years, was admitted to our hospital for exertional dyspnea and pleural effusion. Computed tomography scan and cytological findings of the pleural fluid suggested malignant mesothelioma.
In the postmortem examination, the tumor was pathologically diagnosed as pseudomesotheliomatous adenocarcinoma (PMA) of the lung, classified into pleomorphic carcinoma with adenocarcinoma component according to the new World Health Organization guidelines.
This is the first case report of SSc with PMA.
What Is Malignant Mesothelioma?
Malignant mesothelioma is a cancer that starts in cells in the linings of certain parts of the body, especially the chest or abdomen.
A layer of specialized cells called mesothelial cells lines the inside of the chest, the abdomen, and the space around your heart. These cells also cover the outer surface of most of your internal organs. The lining formed by these cells is called mesothelium.
The mesothelium helps protect your organs by making a special lubricating fluid that allows organs to move around. For example, this fluid makes it easier for the lungs to move inside the chest during breathing. The mesothelium has different names in different parts of the body:
In the chest it is called the pleura.
In the abdomen it is called the peritoneum.
In the space around the heart it is called the pericardium.
Tumors of the mesothelium can be non-cancerous (benign) or cancerous (malignant). .....Read More about Malignant mesothelioma
'Pseudomesotheliomatous' carcinomas are uncommon pathologically heterogeneous tumours with poor prognosis.
The term 'pseudomesotheliomatous adenocarcinoma was coined for these lesions by Harwood et al.
History of asbestos exposure is present one study. A smoking history is present in more than 70% cases.
By light microscopy and immunophenotype many of the tumours mimicked malignant mesothelioma.
Age: Usually occurs in elderly patients.
Clinical symptoms: Chest pain, dyspnea, cough, infiltrative pleural tumour. The symptoms are indistinguishable from those of malignant mesothelioma.
Macroscopic features: Thick, fleshy pleural plaques and masses that extend along the pleura surface and encase the lung.
Microscopic features: Pleura is infiltrated by nests and sheets of cells ; Tumour may focally form glandular structures or tubulo-papillary structures ; Psammoma bodies may be present ; Isolated glands may be present in a fibrous stroma.
Histochemistry: PAS -positive diastase resistant mucin or intracytoplasmic vacuoles are often present in the glandular lumen.
Immunohistochemistry: CEA & low molecular weight cytokeratins are positive in almost all cases. BER-EP4 and Leu M1 may also be positive.
Misdiagnosis of this tumour may have medico-legal implications in asbestos-related compensation claims.